It is well known to use the process of injection molding for creating plastic parts that are used in the automotive industry. Typical molding processes will use a single-colored plastic part that has consistent coloring throughout the entire part. Interior automotive components, such as door panels, traditionally use one color throughout the entire door panel. However, the appearance is not aesthetically appealing. Alternatively, door panel assemblies were created comprising separate inter-connectible parts having one or more colors that fit together to make a final door panel assembly. However, these conventional practices have problems such as the multiple door panel components not fitting together with a clean fit once the assembly is completed. Thus, it would be desirable to overcome these problems.
One of the previous methods of making a multi-colored part utilizing an injection molding machine required machine tooling that had numerous working parts that were necessary for each step of the color molding process. These machines were capable of injection molding parts that have different materials as well. Other methods of manufacturing multi-colored and multi-material plastic parts utilized large band areas, that is the area separating different portions of the plastic part from the rest of the colored plastic part. The band surrounds each object to be covered differently, but the problem with the band areas is that they inherently create dead spots from which non-reflective areas are created. If a reflective part is desired, it would be undesirable to have these dead spots since it is preferred to maximize reflective areas.
Another method of injection molding plastic parts includes the rotary method where the mold is rotated between the shot processer so as to create multiple colored parts. However, rotary machines require large tonnage and hence significant capitol investment.
Accordingly, it is desirable to provide a tool for manufacturing multi-colored plastic parts and multi-material plastic parts that reduce scuffing, warpage and shrinkage. It is also desirable to provide a tool for use in injection molding a multi-colored part through a one step process of not opening the mold during the creation of different colored sections of the final part. It is also desirable to provide a tool that is operable to injection mold a part made of multiple materials that can be injection molded in a single process without opening the mold when the different materials are being shot. Thus, it is preferred to maintain the parting line closed which will reduce scuffing, warpage and shrinkage.
One aspect of the invention includes an improved mold having a pair of clamping plates, a cavity block, a core block, an inner-insert mechanism assembly comprised of retainer pins, retainer slides and slide holders, a spacer mechanism, a moving mechanism retainer plate for holding the spacers in place, springs positioned between the core block and the retainer plate, a clamp plate, an ejector retainer plate, an ejector plate, a manifold retainer plate, a manifold plate, a first shot manifold assembly, a second shot manifold assembly, ejector cylinders, a set of full length parallels, and cylinders for advancing the spacers.
It is also desirable to provide a process of manufacturing a multi-colored part, such as a multi-colored door panel, that overcomes the previously mentioned disadvantages. It will be appreciated that said process can be used on a variety of interior and exterior automotive components, and is not limited to the door panel described herein, which is discussed for illustrative purposed only and is not intended to limit the present invention. It is also desirable to provide a process of manufacturing a multi-colored and multi-material part that decreases cycle time, yet increases part quality, and has improved gas removal during the molding process in order to minimize imperfections in the surface of the part. It would also be desirable to provide a process which results in reducing the amount of scrap material. It is also desirable to provide an improved process of manufacturing a multi-colored part that has improved tolerances with a cleaner fit between the various colored and materialed components within the final part.
According to another aspect of the present invention, a process of making a multi-colored injection molded part includes the steps of providing a mold, closing the mold, injecting plastic of a first color into the mold to create a first part, releasing the machine clamp pressure, adjusting a spacer mechanism to offset an inner-insert from the cavity of the first shot, applying tonnage and then injecting plastic of a second color to another part of the mold to create a second part, and opening the mold and ejecting the completed part. The entire process is performed while maintaining the parting line closed.
Another aspect of the present invention includes a multi-colored part, for example a door panel assembly, with a first portion made of a first type of material, for example, of one color, or of one type of material, and a second portion made of a different material or of a different color. The assembly is made through an injection molding process where the parting line of the mold stays closed during the creation of both parts in order to create the final assembly. Thus, shrinkage and warpage issues are minimized, enhancing fit and quality of the final assembly.
For the following specification taken in conjunction with the accompanying drawings, independent claims, other objects, features, and advantages, the present invention will become apparent to those skilled in the art.